Current mobile systems such as mobile phones or Personal Digital Assistant (PDA) show a continuous increase in complexity due to the ever increasing need for implementing new features and improving existing functions.
In order to reduce cost and to simplify the mechanical design of the smart phones and other application rich networked mobile devices, MIPI has defined a high-speed serial PHY layer (DPHY). MIPI has also specified a layered protocol stack based on OSI protocol stack, namely the Unified Protocol (UniPro), above the PHY layer that provides reliable, networkable; latency aware data transfer between the components or modules in a mobile device. Using error detection and frame re-transmissions, UniPro provides reliability against the errors introduced by noisy mobile environment. Real-time applications like RF to base band communication, video streaming etc that are envisioned to be clients of UniPro need bandwidth guarantees and strict latency/jitter bounds. Re-transmissions will hinder these guarantees.
Real-time traffic is traffic that loses its validity if it is not delivered before the deadline with logical correctness. The real-time traffic is classified as hard real-time or soft real-time. Traffic is hard real-time if it has hard bounds on jitter, while soft real-time could tolerate moderate amount of jitter. However, both of them need guarantees for bandwidth. RF to base band data transmission is an example of hard real-time traffic while compressed video transmission belongs to soft real-time traffic category. A connection oriented data transfer mechanism is employed so that independent guarantees can be provided to each of the connections. An external mechanism determines the bandwidth, jitter and latency requirements of the connections that are set up.